This invention relates to dispensers for dispensing medical grade ultrasound gel onto the body of a patient in a region which is to undergo ultrasound examination. In particular, the present invention is directed to such dispensers that effectively preclude cross-contamination whereby pathogens maybe transferred from one patient to the next as a consequence of the use of a common gel dispensing apparatus which is used for more than one patient.
The particular purpose of the present invention is to provide a dispensing apparatus which will dispense medical grade ultrasound gel onto the body of a patient in such a manner that the risk of cross-contamination from one patient to the next is effectively precluded; while at the same time the comfort of the patient may be assured by dispensing medical grade ultrasound gel which has been warmed to above ambient or room temperature.
In particular, it is a purpose of the present invention to provide a dispenser for medical grade ultrasound gel which assures that the medical grade ultrasound gel remains uncontaminated in the same condition that it has been received from the manufacturer, until such time as the ultrasound gel is dispensed. At the same time, it is assured that harmful pathogens which might be contacted by the gel dispenser from the body of a patient are not transmitted to another patient.
When ultrasound gel is delivered to the body of the patient, it is typically spread around on the body of the patient in the area which is to receive an ultrasound examination. The purpose of the ultrasound gel is to provide coupling between the ultrasound probe and the body of the patient, since the ultrasound waves are not transmissible through air but require a more dense medium.
Typically, ultrasound gel is relatively costly, so it is desired to be able to dispense only enough gel for the ultrasound procedure to be undertaken, while preserving gel in the dispenser being used for the next ultrasound procedure on another patient. Otherwise, it would be necessary to produce single use ultrasound gel containers, probably of varying sizes depending on the amount of gel to be dispensed for any particular ultrasound procedure, and that suggestion is prohibitively expensive. Accordingly, it is most usual that an ultrasound gel dispenser shall contain more ultrasound gel than is required for any specific procedure, and typically the ultrasound gel dispenser is refillable.
However, when an ultrasound gel bottle is used to prepare a patient, which may be human or a veterinary patient, for an ultrasound procedure, the gel dispenser comes into contact with the body of the patient. Therefore, the gel dispenser maybe exposed to body fluids; and if so, the gel dispenser may become contaminated with pathogens such as bacteria, fungi, parasites, and viruses. Of course, such pathogens may then be transmitted to another patient during a subsequent procedure.
The medical grade ultrasound gel which may be dispensed in keeping with the present invention, and as it is dispensed in the prior art devices being discussed, may have differing viscosities. Typically, a gel which is used for diagnostic procedures is less viscous than a gel which is used for therapeutic ultrasound procedures. The reason is, in particular, that medical grade ultrasound therapeutic gels may be placed on a smaller area of the patient of the body than would typically be the case when an ultrasonic diagnostic procedure is to be carried out.
In any event, there is a concern that pathogens can be transmitted to another patient during a subsequent procedure, particularly if the gel dispenser has been positioned around an open wound for a given procedure. This is of even more concern when a gel dispenser may be used on a patient who is suffering from AIDS, or is otherwise immuno-comprised such as is the consequence of following an immuno-suppression drug regimen.
A recent study by a major hospital in Toronto, Canada, showed that more than 100 different kinds of bacteria may be found on a dispenser used for dispensing medical grade ultrasound gel.
Quite often, such dispensers take the form of a bottlexe2x80x94not unlike a ketchup bottle used in household kitchens and the likexe2x80x94from which the medical grade ultrasound gel is to be dispensed. If so, typically the medical grade ultrasound gel is purchased by the hospital or medical laboratory or veterinary clinic in bulk, and the dispensing bottles are filled every five to ten patients in a typical use experience.
It is usual that such gel bottles are managed by being wiped with an alcohol swab before being refilled from the bulk container, and between patients. However, particularly when the gel bottle is to be refilled, it is typically not completely empty before the new gel is to be introduced into the bottle, and therefore the new gel may be exposed to any contaminants or pathogens that are to be found within the gel dispensing bottle. This is because the bottle has only been wiped around the exterior of the cap area and not the interior of the cap or the interior of the bottle. Moreover, the process of refilling the ultrasound gel dispenser bottles is labour intensive, time consuming, difficult, and therefore costly, and it does not fully address or typically ignores the contamination problem. Even if a cleaning and disinfectant procedure has been followed, it is not always effective because it may be possible that the interior of the bottle is not clean.
The present invention presupposes the availability of a source of pressurized medical grade ultrasound gel, to which the dispenser of the present invention is connected in fluid communication with that source. However, the details of the pressurized source of medical grade ultrasound gel are beyond the scope of the present invention.
Moreover, by being in fluid communication with a pressurized source of medical grade ultrasound gel, the assurance is given that each time ultrasound gel is dispensed using the dispensing apparatus of the present invention, the dispensed volume is replaced from the external source of pressurized medical grade ultrasound gel. This assures that the gel remains uncontaminated, because there is no necessity to open the dispenser; and as will be discussed hereafter, there is no opportunity for pathogens to transfer from a patient into the dispenser because of the structure of the dispenser and also because typically a disposable cap member is employed. As will be discussed hereafter, the cap member is very inexpensive, and thus a new, sterilized or at least antiseptic cap member may be used each time the medical grade ultrasound gel is to be dispensed onto a new patient.
The present inventor has quite unexpectedly discovered that a structure for a dispenser apparatus for use in dispensing medical grade ultrasound gel onto the body of a patient, which assures hygienic conditions with respect to the medical grade ultrasonic gel until such time as it is dispensed onto the body of a patient, may be provided using a closed container having a plunger and a sealing plate which will eject the ultrasound gel from the dispensing apparatus while, at the same time, assuring that the dispensing apparatus is refilled from a source of pressurized medical grade ultrasound gel.
Because of the structure of the ultrasound gel dispensing apparatus, particularly when a cap member is employed on the apparatus, contamination of the interior of the dispenser apparatus is precluded. Additional features of the present invention optionally allow for the medical grade ultrasound gel to be heated to above ambient or room temperature, and particularly provide for the use of disposable cap members having significantly low unit costs.
Accordingly, medical grade hydraulic gel dispensers are provided by the present invention which promote at least hygienic and antiseptic conditions, preclude cross-contamination between patients, and assure comfort to the patient by dispensing ultrasound gel which has been warmed.
Kozam U.S. Pat. No. 4,575,375, issued Mar. 11, 1986, teaches a dispensing apparatus which essentially squeezes medication out of a tube, so that an individual patient may self-administer the medication or irrigant into periodontal pockets. Preferably, the medication is in the form of a gel. The operation is, however, not unlike an automated dispensing of toothpaste from a tube thereof.
Frass et al U.S. Pat. No. 4,844,080, teaches an ultrasound contact medium dispenserxe2x80x94ultrasound gelxe2x80x94which pumps gel from a reservoir through a tube to a valve from which the gel is dispensed at the same time that a probe is manipulated. The delivery tube may pass through an electrically powered heater.
A device which is particularly intended for use with ophthalmic gel is taught in Vlasich U.S. Pat. No. 5,048,727, issued Sep. 17, 1991. Here, a single unit dose dispenser is provided, which is coupled with a compressible container that is filled with a gas propellant. When it is desired to dispense the predetermined dose, external pressure is applied to the outer surface of the compressible container having the gas propellant within it, so as to expel the coupling composition. The tube in which the gel is contained is equipped with a removable cap, which is removed just prior to the dispensing procedure so as to preserve the sterility of the gel. Obviously, this apparatus is expensive, since it provides for a predetermined quantity, and is single use.
A paste or gel dispenser is provided in Loudon, U.S. Pat. No. 5,145,095, issued Sep. 8, 1992. Typically, this complicated dispenser is intended for use with toothpaste, and provides a pair of non-return valves which creates an airtight seal with a tube of toothpaste. First, a cavity within the dispenser is primed by squeezing the tube of toothpaste, and then a spring-loaded plunger is activated to displace the toothpaste from the dispensing cavity. As the spring pushes the plunger back, toothpaste is expelled through a second non-return valve onto the bristles of a toothbrush. At the same time, the vacuum which occurs in the dispensing cavity causes further dispensing of toothpaste from the tube into the dispensing cavity for the next toothpaste dispensing procedure.
Last et al U.S. Pat. No. 5,819,986, issued Oct. 13, 1998, provides a dispenser for liquid, gel, granular, or powdered media where a pump outlet is connected to a spray nozzle, and via a suction tube to a connector tube. The refill packing includes an integrally manufactured connector that can be pressed onto the connector tube, and which opens the connector so as to communicate to the interior of the refill packing. The intent is to provide a dispenser that will assure leak-free connection of the refill packing within the outer container therefor.
Hertel U.S. Pat. No. 6,009,887, issued Jan. 4,2000, teaches an adjustable applicator for liquids or gels, medicines or lotions, and the like, which has a pivotal head so that the material to be dispensed may be dispensed on a difficult to reach location such as the user""s back. A pad is provided on the applicator head, and either a lotion is dispensed through the pad, or the pad is pre-soaked with the lotion or gel to be applied. The apparatus may also be used to apply medications or lotions or gels to animals.
The present invention provides a dispenser apparatus for dispensing medical grade ultrasound gel onto the body of a patient in a region which is to undergo ultrasound examination. The dispenser apparatus has a generally cylindrical body having a closed first end and a distal second end which has a dispensing opening therein. A cylinder axis extends along the length of the body.
There is an inlet opening into the interior of the body near the first end thereof, the inlet opening being in fluid communication with a source of pressurized medical grade ultrasound gel.
An elongated shaft extends along the cylinder axis, and has a plunger which is secured thereto near a first end of the shaft, so that the plunger is located near the first end of the body.
A valve element is located at the second end of the shaft, which is remote from the first end. The valve element is adapted to close the dispensing opening when the shaft is in a first, at rest position, and to be in a dispensing position away from the dispensing opening of the body when the shaft is in a second, dispensing position.
The plunger has a first face which faces the first end of the body, and a second face which faces the dispensing opening. There is at least one passageway formed through the thickness of the plunger, so as to extend through the height of the plunger from the first face to the second face thereof.
A plunger return spring is mounted within the body, and it extends between a first fix return spring seat secured within the interior of the body, and the second face of the plunger. The plunger return spring is adapted to urge the plunger from a second position when the shaft is in the second dispensing position towards a first position, whereby the shaft and the plunger secured thereto will assume the first rest position.
There is also a freely moving sealing plate which is mounted for longitudinal movement along the shaft between a first position adjacent the second face of the plunger and a second position which is remote therefrom. The second sealing plate position is below and adjacent to the second face of the plunger.
A sealing plate return spring is also mounted within the body, and it extends between a second fixed return spring seat which is also secured within the interior of the body, and the second face of the sealing plate which is remote from the second face of the plunger. The sealing plate return spring is adapted to urge the sealing plate from a second position near the second fixed return spring seat towards a first position which is adjacent the second face of the plunger.
The sealing plate is adapted to cover the at least one passageway formed in the plunger, when the sealing plate is urged into its first position adjacent the second face of the plunger.
The plunger is adapted to cover the inlet opening when the plunger is in the first, rest position.
Trigger means are provided which are adapted to move the shaft and the plunger from the first position to the second position against the plunger return spring and against the sealing plate return spring. Thus, the valve element is moved into the dispensing position away from the dispensing opening.
Typically, there are a plurality of passageways that are formed through the plunger from the first face to the second face thereof. If so, the sealing plate is adapted to cover the plurality of passageways when it is urged into its first position which is adjacent the second face of the plunger.
Also, typically the second end of the body is configured so as to have an outwardly directed protrusion through which the medical grade ultrasound gel is dispensed when the valve element is moved into its dispensing position. The dispensing opening is formed, therefore, at the end of the outwardly directed protrusion.
When the body of the dispensing apparatus of the present invention has the outwardly directed protrusion, there is typically further provided a cap member which has two axially located open ends opposite each other. The cap member is separable from the body, and is adapted to be fitted to the outwardly directed protrusion. Accordingly, when the cap member is in place, the medical grade ultrasound gel is dispensed through the cap member when the valve element is moved into its dispensing position.
The cap member may be adapted to be threadably secured to the outwardly directed protrusion by cooperating threads which are formed exteriorly on the protrusion and interiorly on the cap member. Also, the cap member may be adapted to be snap fitted to the outwardly directed protrusion.
Typically, a pair of sealing rings is fitted to the outside periphery of the plunger. If so, one of the sealing rings is positioned above the inlet opening and the other of the sealing rings is positioned below the inlet opening, when the plunger is in its first, rest position.
The source of pressurized medical grade ultrasound gel with which the inlet opening is in fluid communication is typically pressurized to within the range of 40 psi to 100 psi.
A check valve may be installed in the fluid conduit which extends from the inlet opening to the source of pressurized medical grade ultrasound gel, thus precluding outflow of ultrasound gel through the inlet opening.
A gel warmer fitment may be adapted to receive the outwardly directed protrusion on the body of the dispensing apparatus, so as to transfer heat from the gel warmer fitment into the medical grade ultrasound gel at least within the body in the region of the dispensing opening.
Usually, therefore, when the medical grade ultrasound gel within the body of the dispensing apparatus of the present invention is warmed, an insulating layer is provided to surround the body.